Quaternary Structure and Certain Allosteric Properties of Aspartase

Williams, Virginia R.; Lartigue, Donald J.

doi:10.1016/s0021-9258(18)99600-6

Cited by 49 publications

(10 citation statements)

References 15 publications

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“…Reciprocal initial velocities were plotted vs. reciprocal substrate concentrations, and all plots were linear with the following exceptions. The aspartate saturation curve exhibits positive cooperativity, and both fumarate and NH4+ saturation curves exhibit negative cooperativity [in agreement with the results of Williams & Lartigue (1967)]. All data were fitted to appropriate rate equations by using the Fortran programs of Cleland (1979b).…”

Section: Methodssupporting

confidence: 65%

“…Aspartase has a M, of 180 000 and is a tetramer (Williams & Lartigue, 1967), while fumarase has a Mr of 190000 and is also a tetramer (Kanarek & Hill, 1964). In addition, aspartase is reported to have a p/of 4.8 (Ellfolk, 1956;Wilkson & Williams, 1961), while the contaminating fumarase has a pi of 5.0 from isoelectric focusing (obtained by Fred S.…”

Section: Methodsmentioning

confidence: 99%

“…The enzyme is specific for the amino acid substrate and fumarate, but NH2OH can substitute for ammonia as a substrate (Emery, 1963). A variety of divalent metal ions will activate the reaction including Mg2+ and Mn2+ (Williams & Lartigue, 1967). The most complete study of the kinetic mechanism for aspartase was carried out by Dougherty et al (1972), who suggested a uni-bi rapid equilibrium random mechanism.…”

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confidence: 99%

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Kinetic mechanism and location of rate-determining steps for aspartase from Hafnia alvei

Nuiry¹,

Hermes²,

Weiss³

et al. 1984

Biochemistry

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Coupled spectrophotometric assays that monitor the formation of fumarate and ammonia in the direction of aspartate deamination and aspartate in the direction of fumarate amination were used to collect initial velocity data for the aspartase reaction. Data are consistent with rapid equilibrium ordered addition of Mg2+ prior to aspartate but completely random release of Mg2+, NH4+, or fumarate. In addition to Mg2+, Mn2+ can also be used as a divalent metal with Vmax 80% and a Kaspartate 3.5-fold lower than when Mg2+ is used. Monovalent cations such as Li+, K+, Cs+, and Rb+ are competitive vs. either aspartate or NH4+ but noncompetitive vs. fumarate. A primary deuterium isotope effect of about 1 on both V and V/Kaspartate is obtained with (3R)-L-aspartate-3-d, while a primary 15N isotope effect on V/Kaspartate of 1.0239 +/- 0.0014 is obtained in the direction of aspartate deamination. A secondary isotope effect on V of 1.13 +/- 0.04 is obtained with L-aspartate-2-d. In addition, a secondary isotope effect of 0.81 +/- 0.05 on V is obtained with fumarate-d2, while a value of 1.18 +/- 0.05 on V is obtained by using (2S,3S)-L-aspartate-2,3-d2. These data are interpreted in terms of a two-step mechanism with an intermediate carbanion in which C-N bond cleavage limits the overall rate and the rate-limiting transition state is intermediate between the carbanion and fumarate.

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Section: Methodssupporting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Kinetic mechanism and location of rate-determining steps for aspartase from Hafnia alvei

Nuiry¹,

Hermes²,

Weiss³

et al. 1984

Biochemistry

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“…L-Malate and L-Aspartate Serve as Important Nutrients for Gut-Luminal H 2 /Fumarate Respiration To further deduce the role of malate and aspartate metabolism during the initial growth, we performed a series of competitive infection experiments in LCM mice and profiled aspA, fumA, fumB, and fumC mutants for colonization defects. The aspA gene encodes for aspartate-ammonia lyase, which converts aspartate to fumarate and ammonia (Figure 4B; Williams and Lartigue, 1967). The genome of S. Typhimurium also encodes three fumarases (encoded by fumA, fumB, or fumC), which are hydro-lyases catalyzing inter-conversion of L-malate and fumarate (Mercado-Lubo et al, 2009).…”

Section: Rb-tnseq Screen Implicates C4-dicarboxylate Transport In Initial Growthmentioning

confidence: 99%

Import of Aspartate and Malate by DcuABC Drives H2/Fumarate Respiration to Promote Initial Salmonella Gut-Lumen Colonization in Mice

Nguyen

Cuenca

Hartl

et al. 2020

Cell Host & Microbe

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“…The activator site is remote from the active site of the enzyme, since the relaxation of inhibitors that bind at the active site is not affected by paramagnetic metal ions bound at the activator site.L-Aspartase (L-aspartate ammonia-lyase, EC 4.3.1.1) catalyzes the reversible deamination of L-aspartic acid to form fumaric acid and ammonia. The enzyme from Escherichia coli is tetrameric, with a subunit molecular weight of 48 000 (Williams & Lartigue, 1967). L-Aspartase has been shown (Ida & Tokushige, 1985;Karsten et al, 1986) to possess an activator site that has the unusual specificity of binding the substrate L-aspartic acid.…”

mentioning

confidence: 99%

L-Aspartase from Escherichia coli: substrate specificity and role of divalent metal ions

Falzone¹,

Karsten²,

Conley³

et al. 1988

Biochemistry

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The enzyme L-aspartase from Escherichia coli has an absolute specificity for its amino acid substrate. An examination of a wide range of structural analogues of L-aspartic acid did not uncover any alternate substrates for this enzyme. A large number of competitive inhibitors of the enzyme have been characterized, with inhibition constants ranging over 2 orders of magnitude. A divalent metal ion is required for enzyme activity above pH 7, and this requirement is met by many transition and alkali earth metals. The binding stoichiometry has been established to be one metal ion bound per subunit. Paramagnetic relaxation studies have shown that the divalent metal ion binds at the recently discovered activator site on L-aspartase and not at the enzyme active site. Enzyme activators are bound within 5 A of the enzyme-bound divalent metal ion. The activator site is remote from the active site of the enzyme, since the relaxation of inhibitors that bind at the active site is not affected by paramagnetic metal ions bound at the activator site.

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Quaternary Structure and Certain Allosteric Properties of Aspartase

Cited by 49 publications

References 15 publications

Kinetic mechanism and location of rate-determining steps for aspartase from Hafnia alvei

Kinetic mechanism and location of rate-determining steps for aspartase from Hafnia alvei

Import of Aspartate and Malate by DcuABC Drives H2/Fumarate Respiration to Promote Initial Salmonella Gut-Lumen Colonization in Mice

L-Aspartase from Escherichia coli: substrate specificity and role of divalent metal ions

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